Select can, remove lid, shake out worms......

More than anything else with these cars I think everyone has a view on brakes, ranging from "OEM is fine, the best in the day" to "we must have made improvements in the last 50yrs ?".
Joji (Grumblebuns) did a brief survey of what was available
https://www.lotuseuropa.org/LotusForum/index.php?topic=2437.0 although as always time moves on and there's other views around.
I've used Greenstuff on both the Elan & Europa at some point but moved away. These days I have the Mintex 1144 in the Elan, Europa and Elise but only this week I picked up a post on Lotuselan.net that said the 1144 was NLA, citing the use of copper as the prime reason. The replacement is MRM1802 for the type 14 caliper which is classed as a track pad, but there's more detail in the post;
https://forums.lotuselan.net/t/mintex-1144-brake-pads/56263If you are running 13" wheels you're limited on what you can fit underneath. You'll get the 245mm disc & type 16 caliper from the GT6 underneath but need new caliper mounting brackets. I have this on the Elan after removing the servo and yep, it's ok. I know one member has fitted vented discs and spaced out the original calipers which seems a neat option and IIRC he was pleased with the results. For an easy upgrade I think the Banks kit has been a go-to option for standard wheels, he must know more about the brakes on the standard cars than anyone else around.
The big snag IMO is that the brake balance is well away from what's normal these days. I think RichardH's spreadsheet came up with something like 26% contribution from the rears, a massive F/R imbalance and although you don't notice it in the dry, that's why we have front wheel lock on wet roads.
Hence a rear disc conversion would be my best bang/buck rather than fitting better front calipers/discs and leaving the rear of the car alone.
If you are prepared to move to larger wheels, things get more flexible in both brakes & tyre choices. I'm running 15" wheels with 50 series tyres for the same overall diameter, something to consider if tyre choice is more important than originality.
For brakes I did a thread back in 2016, briefly it's 260mm discs front & rear, standard 14F calipers at the front, Renault 34mm piston calipers at the rear. 1144 front pads, Ultimax rear, no servo. I've since updated it to having BMW Mini 36mm rear calipers which if I'm honest didn't make a massive difference but improves the theoretical F/R balance. It stops like a modern car.
https://www.lotuseuropa.org/LotusForum/index.php?topic=1699.msg15446#msg15446Even so that's not perfect and personally I struggled to get a closer F/R balance even with the clean sheet approach, but (again IMO) it's better than the disc/drum setup.
Brian